Combined heating/hot water system for a vehicle

ABSTRACT

Combined heating/hot water system ( 10 ) for a vehicle ( 12 ), comprising an air heating device ( 14 ), at least one air duct ( 20, 22, 24 ), by means of which the air heating device ( 14 ) is connected by air to an interior ( 30 ) of the vehicle ( 12 ) for heating, a fan ( 18 ), by means of which air heated in the air heating device ( 14 ) may be introduced into the interior ( 30 ) of the vehicle ( 12 ) for heating, a hot water reservoir ( 16 ) arranged in a recess ( 15 ) in the air heating device ( 14 ), a first pipe duct ( 36 ), by means of which the hot water reservoir ( 16 ) may be hydraulically connected to a tap ( 34 ) in the vehicle ( 12 ) and a second pipe duct ( 38 ), by means of which the hot water reservoir ( 16 ) is hydraulically coupled to a water tank ( 32 ), wherein at least one of the pipe ducts ( 36, 38 ) is arranged in one of the air ducts ( 20, 22, 24 ).

This application is a 35 U.S.C. §371 National Stage entry ofPCT/DE2006/002277, filed Dec. 19, 2006, which claims priority fromGerman Patent Application No.: DE 10 2006 007 777.6, filed Feb. 20,2006, the contents of which are herein incorporated by reference.

The invention relates to a combined heating/hot water system for avehicle and a vehicle comprising a combined heating/hot water system.

Such combined heating/hot water systems may be used, for example, forheating and for supplying hot water for campervans, motorhomes,watercraft and the like.

Such a combined heating/hot water system for a vehicle is, for example,known from the German utility model DE 20 2004 003 914 U1. An air heaterfor heating an airflow, as required, is connected to an air-fluid-heatexchanger, via which heat may be discharged to a heat sink. The heatsink may, for example, be a system for water for domestic use. Thus acombined heating/hot water system for a vehicle may be provided in whichonly one source of energy has to be used.

The object of the invention is to provide a combined heating/hot watersystem for a vehicle which is safe in operation, has a high degree ofenergy efficiency and offers comfortable handling by the user.

The object is achieved by the features of the independent claims.Advantageous developments of the invention are characterized in thesub-claims.

According to a first feature, the invention is characterized by acombined heating/hot water system for a vehicle comprising an airheating device, at least one air duct, by means of which the air heatingdevice is coupled by air to an interior of the vehicle to be heated, afan by means of which air heated in the air heating device may beintroduced into the interior of the vehicle to be heated, a hot waterreservoir arranged in a recess of the air heating device, a first pipeduct by means of which the hot water reservoir is hydraulically coupledto a tap arranged in the vehicle, and a second pipe duct by means ofwhich the hot water reservoir is hydraulically coupled to a water tank,at least one of the pipe ducts being arranged in one of the air ducts.

Firstly a temperature control of the at least one pipe duct, which isarranged in the at least one air duct, may be achieved thereby. This isparticularly advantageous as, generally, when the combined heating/hotwater system is out of operation the temperature of the water in thepipe ducts of the hot water system returns to ambient temperature. Bymeans of the arrangement of the pipe duct in the at least one air ductit is possible to prevent this, as the pipe duct in this case may beflushed with temperature-controlled air. Moreover, a space-saving designof the combination of the air duct and pipe duct is possible.

In a preferred embodiment of the invention, the first air duct isarranged downstream of the air heating device and upstream of theinterior of the vehicle to be heated and at least one of the pipe ductsis arranged in the first air duct. Thus it is possible to control thetemperature of the pipe duct arranged in the air duct by means of heatfrom the air heating device. This is particularly advantageous if theair heating device is a low temperature heating device, as then anadaptation of the temperature of the at least one pipe duct to thetemperature of the air heated by the air heating device is possible in aparticularly simple manner. If the combined heating/hot water system isout of operation, depending on the arrangement of the combinedheating/hot water system, by creating a convection flow between thecombined heating/hot water system and the interior of the vehicle to beheated, the at least one pipe duct may therefore be flushed with warmair and thus temperature-controlled.

In a further particularly preferred embodiment of the invention, thesecond air duct is arranged upstream of the air heating device anddownstream of the interior of the vehicle to be heated and at least oneof the pipe ducts is arranged in the second air duct. This allows aparticularly even temperature control of the at least one pipe duct byheat from the interior of the vehicle to be heated. Heat from theinterior of the vehicle to be heated may thus flow around the at leastone pipe duct and control the temperature of said pipe duct. If thecombined heating/hot water system is out of operation, in thisembodiment it is also possible for a convection flow to be createdbetween the combined heating/hot water system and the interior of thevehicle to be heated so that the at least one pipe duct is flushed withhot air and thus may be temperature-controlled.

In a further preferred embodiment of the invention, the air heatingdevice comprises a heating device which may be operated by a liquidfuel. This is particularly advantageous, as the combined heating/hotwater system in this case may be operated by the fuel, which is alsoused as fuel for the vehicle, for example gasoline or diesel fuel. It isthus possible to use the arrangement of the at least one pipe duct inthe air ducts for heating/hot water systems, which are operated withgasoline or diesel fuel.

According to a second feature, the invention is characterized by avehicle with a combined heating/hot water system which is arranged on anouter face of the vehicle. Thus considerable scope for the design of thecombined heating/hot water system is possible, in particular with regardto its size and shape. Moreover, more space for the occupants of thevehicle may be provided in the interior of the vehicle to be heated.Preferably, the combined heating/hot water system is arranged under thevehicle or on the vehicle. It is thus possible that a convection flow iscreated between the combined heating/hot water system and the interiorof the vehicle to be heated and thus hot air flows around the at leastone pipe duct arranged in the at least one air duct and istemperature-controlled.

Embodiments of the invention are described hereinafter with reference tothe schematic drawings, in which:

FIG. 1 shows a schematic view of a first embodiment of a combinedheating/hot water system for a vehicle,

FIG. 2 shows a schematic view of a second embodiment of the combinedheating/hot water system for a vehicle, and

FIG. 3 shows a schematic view of a third embodiment of the combinedheating/hot water system for a vehicle.

Elements of the same construction or function are provided with the samereference numerals in all the figures.

FIG. 1 shows a schematic view of a first embodiment of a combinedheating/hot water system 10 for a vehicle 12. The combined heating/hotwater system 10 has an air heating device 14, a first air duct 20 and asecond air duct 22, by means of which the air heating device 14 iscoupled by air to the vehicle 12, in particular an interior 30 of thevehicle 12 to be heated. A hot water reservoir 16, a heating device 17and a fan 18 are arranged in a recess 15 of the air heating device 14.The hot water reservoir 16 is used for storing hot water for use in thevehicle 12.

The heating device 17 may be an electrical heating device or a heatingdevice for burning fossil fuels, in particular gaseous or liquid fuels.In particular, the heating device 17 may be operated by liquid fuels,which are already used as motor fuel for driving the vehicle 12, such asfor example gasoline or diesel fuel.

The fan 18 arranged in the air heating device 14 may be arranged in theflow direction upstream or downstream of the heating device 17. The fan18 may also be arranged outside the air heating device 14, for examplein the interior 30 of the vehicle 12 to be heated.

The first air duct 20, the second air duct 22 and the air heating device14 are provided with a heat insulating layer 26 through which the heatlosses of the air heating device 14, as well as the first air duct 20and the second air duct 22 may be reduced. The heat insulating layer 26may also be arranged only in partial regions of the first air duct 20,the second air duct 22 and the air heating device 14.

A water tank 32 is arranged in the vehicle 12. The water tank 32preferably serves for providing water for domestic use. The water tank32 may also be arranged outside the interior 30 of the vehicle 12 to beheated or outside the vehicle 12. In the vehicle 12 a tap 34 is furtherarranged via which cold water or preferably water for domestic useheated by the air heating device 14 may be removed from the water tank32. The tap 34 is preferably arranged in the interior 30 of the vehicle12 to be heated. It may, however, also be arranged at other points inthe vehicle 12.

By means of a first pipe duct 36, the hot water reservoir 16 ishydraulically coupled to the tap 34 arranged in the vehicle 12. A secondpipe duct 38 produces a hydraulic coupling between the hot waterreservoir 16 and the water tank 32. The pipe ducts 36, 38 are arrangedin the second air duct 22. In the embodiment of the invention shownhere, the air heating device 14 is arranged on an outer face 28 of thevehicle 12. It may, however, also alternatively be arranged in thevehicle 12, in particular in the interior 30 of the vehicle 12 to beheated.

Hereinafter the mode of operation of the first embodiment of thecombined heating/hot water system 10 for a vehicle 12 is to be describedin detail.

During operation of the air heating device 14, air from the interior 30of the vehicle 12 is introduced by means of the fan 18 in a flowdirection 40 into the air heating device 14. The air flows through theheating device 17, said air being heated and blown in a flow direction42 via the first air duct into the interior 30 of the vehicle 12 to beheated. By means of the heating device 17, the hot water reservoir 16 isheated further.

If no heat is required for heating the interior 30 of the vehicle 12 tobe heated, as for example in summer, the heating device 17 may also beused solely to heat up the hot water reservoir 16. The air heatingdevice 14 may in this case be operated in outside air mode, outside airbeing sucked in from the surroundings by means of the fan 18 via flaps,not shown, and being able to be discharged again into the surroundings.

If hot water is drawn from the tap 34, fresh water flows from the watertank 32 into the hot water reservoir 16, where it may be heated by theair heating device 14. As, during operation of the air heating device14, air from the interior 30 of the vehicle 12 to be heated iscontinuously supplied via the second air duct 22 into the air heatingdevice 14, the temperature of the pipe ducts 36, 38 which convey water,may be maintained at least at a temperature which is close to thetemperature of the interior 30 of the vehicle 12 to be heated.

If the air heating device 14 is out of operation, by coupling theinterior 30 to be heated with the recess 15 of the air heating device 14by air, it is ensured that similar temperatures prevail in the interior30 to be heated, in the recess 15 of the air heating device 14, in thefirst air duct 20 and in the second air duct 22, so that also in thisoperating state of the air heating device 14, the pipe ducts 36, 38 maybe maintained approximately at the temperature of the interior 30 of thevehicle 12. This is particularly advantageous, as in this case it may beprevented that the temperature of the water for domestic use in the pipeducts 36, 38, even in colder seasons, falls too sharply or even, forexample in winter, that the water for domestic use freezes in the pipeducts 36, 38. This applies, in particular, when the air heating device14 is only out of operation for a relatively short time period i.e. halfa day or an entire day.

In FIG. 2, a second embodiment of the heating/hot water system 10 for avehicle 12 is shown. It differs from the first embodiment in thatbetween the recess 15 of the air heating device 14 and the interior 30of the vehicle 12 to be heated, a third air duct 24 is arranged, thepipe ducts 36, 38 being arranged in the third air duct 24. Air does notactively flow through the third air duct 24 i.e. by means of a fan.

The arrangement of the pipe ducts 36, 38 in the third air duct 24 isparticularly advantageous, as in such an arrangement, even in the casethat an airflow in the first air duct 20 and the second air duct 22 isinterrupted, for example by closing air flaps, not shown, in the firstair duct 20 or in the second air duct 22, hot air may flow past the pipeducts 36 and 38 and may control the temperature of said pipe ducts. Ifthe air heating device 14, for example, is arranged below the interior30 of the vehicle 12, discharged heat from the hot water reservoir 16via the recess 15 of the air heating device 14 may pass by a convectiveflow via the third air duct 24 past the pipe ducts 36 and 38 into theinterior 30 of the vehicle 12. Thus it may be achieved that thetemperature of the pipe ducts 36, 38 may be controlled by the dischargedheat of the hot water reservoir 16. With the arrangement of the airheating device 14, for example, above the interior 30 of the vehicle 12,a convection flow may be formed from the interior 30 of the vehicle 12to be heated to the recess 15 of the air heating device 14. Thus thetemperature of the pipe ducts 36, 38 may be controlled by the heat fromthe interior 30 of the vehicle 12.

In the third embodiment shown in FIG. 3 of the combined heating/hotwater system 10 for a vehicle 12, the first pipe duct 36 and the secondpipe duct 38 are arranged in the first air duct 20 downstream of the airheating device 14 and upstream of the interior 30 of the vehicle 12 tobe heated.

During operation of the air heating device 14 by means of the fan 18,air is introduced in the flow direction 40 from the interior 30 of thevehicle 12 to be heated into the recess 15 of the air heating device 14.The air flows through the heating device 17 and is heated. The heatedair finally flows via the first air duct 20 in the flow direction 42into the interior 30 of the vehicle 12 to be heated. The temperature ofthe pipe ducts 36 and 38 arranged in the first air duct 20 is controlledby means of the hot air flow emerging from the heating device 17. Thearrangement of the pipe ducts 36 and 38 in the first air duct 20downstream of the air heating device 14 and upstream of the interior 30of the vehicle 12 to be heated is particularly suitable for lowtemperature heating systems, i.e. in particular when the temperatures ofthe air after leaving the air heating device 14 are below 100 degreesCelsius, so that the temperature of the water for domestic use in thepipe ducts 36 and 38 may not be greater than the boiling point of water.

It is understood that, depending on requirements, combined heating/hotwater systems 10, in which only one pipe duct 36, 38 is arranged in oneof the air ducts 20, 22, 24, are also encompassed by the invention.Thus, for example, only the first pipe duct 38, with which the hot waterreservoir 16 is hydraulically coupled to a tap 34 arranged in thevehicle 12, may be arranged in one of the air ducts 20, 22, 24.Alternatively, only the second pipe duct 36, with which the hot waterreservoir 16 is hydraulically coupled to a water tank 32, may bearranged in one of the air ducts 20, 22, 24. The respective other pipeducts 36, 38 may in these cases, for example, be guided directly fromthe hot water reservoir 16 respectively without a guide mechanismthrough the air ducts 20, 22, 24 to the tap 34 or to the water tank 32.

The invention claimed is:
 1. A combined heating/hot water system for avehicle, comprising: an air heating device, at least one air duct bymeans of which the air heating device is coupled by air to an interiorof the vehicle to be heated, a fan for introduction of air into the airheating device and by means of which air heated in the air heatingdevice is introduced into the interior of the vehicle to be heated, ahot water reservoir arranged in a recess of the air heating device, afirst pipe duct by means of which the hot water reservoir ishydraulically coupled to a tap arranged in the vehicle, and a secondpipe duct by means of which the hot water reservoir is hydraulicallycoupled to a water tank, at least one of the first and second pipe ductsbeing arranged in one of the air ducts.
 2. The combined heating/hotwater system of claim 1, characterized in that a first air duct isarranged downstream of the air heating device and upstream of theinterior of the vehicle to be heated, and in that at least one of thepipe ducts is arranged in the first air duct.
 3. The combinedheating/hot water system of claim 1, characterized in that a second airduct is arranged upstream of the air heating device and downstream ofthe interior of the vehicle to be heated, and in that at least one ofthe pipe ducts is arranged in the second air duct.
 4. The combinedheating/hot water system of claim 1, characterized in that the airheating device comprises a heating device which may be operated by aliquid fuel.
 5. The vehicle comprising a combined heating/hot watersystem of claim 1, characterized in that the combined heating/hot watersystem is exterior to an outer face of a vehicle interior.
 6. The systemof claim 5, wherein the air heating device has a heat insulating layer.7. The system of claim 6, wherein each of a first air duct and a secondair duct has a heat insulating layer.